1. Field of the Invention
The present invention relates generally to electronic item identification systems and more particularly, to a radio frequency (RF) identification tag and method for identifying an item to or with which the tag is attached or associated, respectively, wherein each tag includes a plurality of circuits having a capacitance.
2. Background of the Related Art
Conventionally, transportation of goods is conducted by utilizing railways, trucks, ships, airplanes and so on. In recent years, however, transportation of light-weight parcels by small trucks or the like, called Takuhaibin, have become very popular because of its low cost. In this type of transportation, a forwarding agent collects and delivers parcels to destinations in a short period of time. This transportation is known by its simple procedure and fast delivery of parcels.
In such transportation, parcels are attached with a label on which a sender, a destination and so on are filled in. A delivery man looks at the labels on the parcels and thereby checks the destinations and conducts sorting out of the parcels. Recently, checking of destinations and sorting out of the parcels have also been conducted in the following manners: in one method, destinations are coded, and sorting out of the parcels are conducted using the coded destinations. In another method, a delivery man carries with him or her a bar code system, and parcels carry on them a label on which bar codes representing a sender, destination and so on are printed.
However, in this transportation method, parcels are often delivered to a wrong destination or lost before they reach the destinations. Such accidents cost a forwarding agent substantial sums of money for investigation and compensation.
These accidents may be decreased by reinforcing visual checking of parcels. However, reinforcement of visual checking of parcels increases cost and prolongs the time for delivery. In any way, it requires manpower and limits reliability.
Currently, electronic item identification systems are in widespread use today to identify a variety of items. A first type of electronic item identification system commonly used in industry is one in which bar code labels are used to identify items. These types of electronic item identification systems are typically used by supermarkets, distributors, shipping services and clothing retailers to scan the bar code labels for quick retrieval of an item""s price or other information.
The way conventional bar code identification systems work is as follows. Bar codes labels are made up of a series of lines of varying widths or thicknesses to establish a code which can be read by a scanner. A bar code label is usually read by a laser scanner. The data from the scanner is electronically fed to a receiver which determines the identification code or number associated with the bar code label. The identification code or number is then sent to a central processing unit or computer where each code or number is matched to data stored on a master list such as item price or other information. The central processing unit or computer then electronically sends the stored data associated with the identification code or number to the cash register or other tabulator to arrive at a final total or tabulated result.
Another system of electronic item identification uses radio frequency (RF) identification tags to identify items. Radio frequency (RF) identification tags can be used to identify a variety of items to which the tags are attached or otherwise associated. In particular, radio frequency (RF) identification tags are currently used to identify passengers, luggage, library books, inventory items and other articles. Radio frequency (RF) identification tags will allow electronic identification of people or objects, moving or stationary, at distances of several feet.
Prior art devices short out capacitors during interrogation and thus the circuit can never be restored to its original frequency to be read over again. It is therefore desirable to develop an electronic item identification system in which the radio frequency (RF) identification tag can be read any number of times while still generating the same binary number as was read the first time and in this manner the tag can be reused.
It is also desirable to develop an electronic item identification system in which a radio frequency (RF) identification tag has numerous circuits made up of capacitor/inductor coil pairs at evenly spaced intervals on the surface of the tag so that the presence or absence of a circuit or the circuit""s functionability could be programmed at the point of use with inexpensive equipment.
It is a feature and advantage of the present invention in providing an electronic item identification system in which the radio frequency (RF) identification tag can be read any number of times while still generating the same binary number as was read the first time and in this manner the tag can be reused.
It is another feature and advantage of the present invention in providing an electronic item identification system in which a radio frequency (RF) identification tag has numerous circuits made up of capacitor/inductor coil pairs at evenly spaced intervals on the surface of the tag so that the presence or absence of a circuit or the circuit""s functionability could be programmed at the point of use with inexpensive equipment.
In accordance with one embodiment of the invention, a tag uses radio frequency waves transmitted from a scanning device in order to identify an item to which the tag is attached or with which the tag is associated. The tag includes a first insulating layer having a top surface and a bottom surface, and resonant circuits formed on the first insulating layer. Each of the resonant circuits are formed on one of the top surface and the bottom surface of the first insulating layer and have a resonant frequency associated therewith. Each of the resonant circuits include capacitance and inductance elements. The capacitance and inductance elements include an inwardly spiralled coil connected to an outwardly spiralled coil. The tag is associated with a binary number established by a pattern of ones and zeros depending on each circuits"" resonance or nonresonance, respectively.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.